Sea Dragon is a side-scrolling game for the TRS-80 computer, written by Wayne Westmoreland and Terry Gilman, and released in 1982 by Adventure International. It was one of the most popular games for the TRS-80. Its success on the TRS-80 led to it being ported to the Apple II, Atari 400/800, and the TRS-80 Color Computer.
The game concept and gameplay are similar to the Scramble, although the ending is more reminiscent of the game Phoenix. The player controls a submarine that can shoot torpedoes both forwards and upwards. The gameplay involves navigating "past underwater mountains and through labyrinthine passages while avoiding webs of explosive mines that rise from the sea bottom. Additional dangers include mine-dropping ships, enemy attack stations, falling stalactites, and deadly lasers—any of which could keep you from your ultimate goal: destruction of the incredibly powerful nuclear reactor at the end of the undersea course." (Adventure International catalog, 1982)
The Apple II version of Sea Dragon was notable because of its use of a digitized voice that says "Sea Dragon!" When the user starts the game, he or she is told, "Captain! Your ship's computer is now ready. Please wait while I initialize systems!", and during the game will be informed, "Air level critical!", "Checkpoint!", and "Approaching maximum damage!" This use of speech was a novelty, as the Apple II speaker is usually only able to emit a one-bit click. Programming Sea Dragon to play back an audio sample, using only a one bit sound generator, was thus an interesting technical achievement, shared with several other 1982 Apple II games: Dung Beetles, Creepy Corridors, and Plasmania.